Amino-triazolinone according to the present invention is prepared using hydrazine as a starting raw material and poisonous phosgene as an intermediate material, as shown in the following Reaction Formula. Such a process was first developed by Bayer AG in Germany and produces amicarbazone, which is a prominent plant growth regulator. Amicarbazone is mainly used in large farms producing sugar cane and corn, and with increasing demand for sugar cane as a raw material for bioethanol and a raw material for raw sugar, demand for herbicides is also increasing.

Although methods for preparing amino-triazolinone have been registered as patents since the amino-triazolinone of the present invention was publicly known in the art (see J. Heterocyclic Chem., 21(6), 1769-74 (1984)), most of these patents relate to a method for preparing amino-triazolinone using phosgene. Representative inventions using phosgene are disclosed in detail in U.S. Pat. No. 4,952,701 (filed in 1988), U.S. Pat. No. 5,693,821 (filed in 1996) and U.S. Pat. No. 5,912,354 (filed in 1998), and examples of inventions relating to amicarbazone are disclosed in detail in U.S. Pat. No. 5,194,085 (filed in 1991) and U.S. Pat. No. 5,625,073 (filed in 1995) (see the published patent documents for details).